﻿using System;
using System.Collections;

namespace ConferenceSystem
{
    public abstract class cl_0423_System
    {

        protected ArrayList Join_meet = new ArrayList();

        public abstract void Message();

        public void attach(cl_0423_MeetingObserver meetingObserver)
        {
            Join_meet.Add(meetingObserver);
        }

        public void detach(cl_0423_MeetingObserver meetingObserver)
        {
            Join_meet.Remove(meetingObserver);
        }
    }
}